426 Backfires

2 replies to this topic
  • Phatjonny

Posted January 22, 2007 - 09:24 AM


OK, time for a newbie question...My 2000 426 backfires on deceleration. I haven't been riding in about a year, the last time I did ride it, it was backfiring, so after doing a search on TT, I figured the muffler might need to be repacked, so I did that. Just got back from riding over the weekend, still backfires. I have a White Bros 1st Gen E Series Carbon Fiber Pipe w/ the White Bros head pipe as well. The pipe has these "tuneable discs" at the end of the muffler. I think 10-12 come with the muffler and you can put more on or take some off. Think I should try messing around with these discs or do you think it would be jetting or ???

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  • grayracer513

Posted January 22, 2007 - 09:36 AM


From the Common Threads Sticky:


  • yzsurfer

Posted January 22, 2007 - 01:16 PM


I have a 2000 that did the same thing. It was more than just the decel popping that they all do a little. After many attempts, I (was directed) to the pilot jet. Open the float bowl with a 17mm and there are 2 jets. The forward one is the pilot jet and has a screwdriver slot in it. I loosen the carb clamps and turn the carb sideways so I don't have to remove it from the bike. The pilot is about an inch and half long, skinny tube that has a few holes in the upper end. Most people put in a 45 pilot (about 6 bucks) instead of the 43 stock. Especially with an aftermarket exhaust. I could see through the small hole in mine, but it still was blocked ever so little. Take a piece of wire and run it through there. I could see a larger hole after doing this. Bike ran great after this with no back firing or popping.

Good luck,


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